Generally, chairs are being used as a required necessity for human life for a long time. Also, time to use a chair increases as society is modernizing. Accordingly, the shape and kind of chairs are also being developed in various ways according to the purpose and place of the use.
Recently, a chair with a backrest formed into two divided parts is suggested and being widely used to prevent and correct spinal deformity. In addition, chairs that massage or acupressure shoulders and spinal areas by disposing an electric motor on the inner side of the backrest and operating a massage member by the electric motor are being variously suggested.
However, a typical chair for spinal correction is equipped with a backrest merely divided into two parts, but unable to implement an additional acupressure or massage function. A typical electric motor massage chair is not only expensive but also requiring a separate power. Accordingly, there is a limitation in that the chair could not be used regardless of place.
Taking the limitation into consideration, a chair is disclosed in Korean Patent No. 10-0981318 own by the present applicant. The chair includes a backrest comprising two parts each disposed separately rotatable and formed with a massage piece such that the chair can massage a user with the massage piece being in contact with the user's back when the user pushes back the backrest. Since the chair is very complex in structure and performs massage in response to physical movement of a user, massaging area was very limited. Particularly, there is a limitation in that the chair could not be used as an ordinary chair at usual time but used merely for massage.
Taking the limitation into consideration, a “chair having two piece back panel with massager” is disclosed in Korean Patent No. 10-1003756. The chair includes two support members concentrically rotating between two backrests rotatably fixed on a separate pivot axis and massagers configured to massage a user's back and spinal area when stopping protrusions formed on each backrest and each support member rotate in engagement with each other in compliance with a user's motion to fold the backrests back.
However, a chair having two piece back panel with massager according to the embodiment of Patent No. 10-1003756 is also very complex in structure. The chair has a limitation in that a user has to push back his/her back and arm area in a big motion for spinal and back massages. There is a possibility that a user suffers a pain and an injury when his/her clothes or skin gets caught between stopping protrusions during the engaged rotation of a backrest stopping protrusions and a support member's protrusions. Even though the chair has some massaging effect since each protrusion massages from the center of spine toward outer side complying with pushing back action on each backrest by the user, the chair does not perform corrective action to gather spinal area to the center.